In this Opening Session of the 2nd Global Grand Challenges Summit, the distinguished speakers before me have already done a great deal to set the scene and lay out some of the big issues and possible ways forward. No doubt we will hear more about the astounding developments we are seeing in information communications technology (ICT) and other technologies in many sectors and of the opportunities they bring to help tackle our grand challenges. And if I look through the prism of my own sector−design engineering in the built environment−I see exactly the same thing: Rapid advances in our thinking are taking place at dizzying speeds. Much of that is being driven by interdisciplinary collaborations ranging well beyond the orbit of traditional engineering and construction.

I would like to share with you some thoughts about the role of our cities in tackling these grand challenges.

Rapid urbanization means we are of course to have close to three-quarters of humanity living in urban areas by 2050. From where we are today, we are adding 5.5 million people to our cities every month! And by that time, we are quite likely to have added another 2 billion people to the planet, most of them in the cities.

The number of “mega-cities” with a population of over 10 million people has gone from just one in 1950 to around 35 today and there are 560 cities in the world with more than 1 million population. The number is increasing, and the developing world is the host to most of these expanding cities. This is a massive challenge that will continue to grow.

Since we know that cities already account for 60% of global drinking water, 75% of energy consumption, and contributing up to 80% of greenhouse gas emissions, that is a big deal. Many cities are vulnerable to natural disasters and human errors. Not to mention the more pressing issues such as traffic congestion and air pollution.

And yet, it also represents the best opportunity we have to make real progress for the future−we design our new cities to be safer, far more efficient, sustainable, and resilient than our previous efforts. The best way to do that, of course, is through collaboration−collaboration between cities.

Even just in my own firm, for example, we have been working closely over the last few years with international initiatives such as the Rockefeller Foundation’s 100 Resilient Cities programme, the United Nations Human Settlements Programme (UN-Habitat), and the World Economic Forum’s “CEO Climate Leadership Group.” The C40 Cities Climate Leadership Group consists initially of 40 cities, but has grown to 63, of the world’s largest cities. These and similar initiatives taking place around the world point the way to what we need for the future. Efforts aimed at mapping actions; determining successful outcomes; and then transferring the knowledge and lessons about what works, and what does not, to city authorities across the globe.

And cities facing similar challenges can learn a great deal from their colleagues around the globe-without having to completely re-invent the wheel each and every time, e.g.,

• New Orleans and Manila are building their infrastructure for resilience against disaster;

• Los Angeles and Perth are learning the lessons of how to mitigate urban sprawl;

• Qatar and Mumbai are implementing new water management strategies;

• Hong Kong and Tokyo are illustrating the energy efficiency inherent in compact cities; and

• Berlin and London are retrofitting their infrastructure to become more liveable at higher densities.

In the last couple of years, major cities have doubled their climate change actions, particularly those involved in Smart Cities initiatives [ 1− 3].

So while rapid urbanization may present its own challenges, global collaboration means we can raise the pace of innovation so that the next generation of cities is far better than the last. This need could not be more urgent.

This is because, just to keep pace with projected global gross domestic product (GDP) growth will require an estimated $57 trillion USD in infrastructure investment between now and 2030 [ 4].

That $57 trillion USD represents more than the total estimated value of today’s infrastructure. In other words, we may be about to double, or build the entire world’s infrastructure all over again in the next 15 years.

So this is the time to make sure that we learn from past mistakes and build it better. Or we create a blight that will take decades to eradicate.

This is the time to ensure that we create the smarter, more sustainable and resilient future we all want to see. And this is the time to build a future where we recognize the co-dependence between our social, economic, and environmental needs, and design our infrastructure and our cities accordingly.

Compact City is the predominant model for developing cities, where energy efficiency is achieved through density, high-rise and mix-used buildings, together with an efficient public transport system. Let us now take a forward-looking view of just some components of such a city: buildings, transportation, and urban form.

Ultimately, to achieve resilience and sustainability, city is best treated as a system or a system of subsystems (Fig. 14). This is because the design and operation of each element of its infrastructure are inter-related, e.g., in energy consumption (Fig. 15). So solutions to grand challenges we face in cities must therefore be developed by a holistic and integrated approach, which also brings opportunities for new businesses and economic development.

And in the end, cities must not wallow at a “survival” or “basic” level. We must also seek to create a built-environment with amenities, spaces, and places that are enjoyable and inspiring to their users (Fig. 16).

Clearly, there are multiple ways in which we can create better, safer, more resilient, more efficient, and, crucially, more liveable cities. We will need to keep up the rate of innovation and development−and we will need to embed excellence in design across the globe−not just on a few specific cases. That is the only way to make sure that when we, in effect, build the world’s existing infrastructure all over again, we do it in the right way. By smart I mean that the new approach must use a contemporary method that allies cutting-edge innovation cultures and new technologies with an understanding of the social and human elements that make a city productive, efficient, and human.

And that takes me back to the main point of this article:

• We will win or lose many of our global challenges in our cities, so we need interdisciplinary collaboration in global design.

• We will need new ways for our engineers and scientists to work together with social scientists, artists, and the local communities.

• And we will certainly need the designers of our future to develop far broader skills.

• We need engineering education that incorporates challenge-based approaches where we set problems to allow people to acquire the necessary skills and solve real-world problems.

• We need to drive innovation in specific disciplines while sharing knowledge across people and cultures around the globe.

• This is how we move from global learning to local action, harnessing the best brains and skills not just of China, the UK or the USA, but of all countries.

• So we need new thinking−both incremental improvements as well as new and disruptive technologies.

• And we need to move from component-based to system-based innovation.

Looking around today, I am greatly reassured that we can do it−and we will do it.

I am optimistic. I hope that you are, too.

Acknowledgements

The author thanks Arup Group Ltd. for permission to use the figures in this article.